Data Logger help needed

[Brian d marge]

Ok
I have decided that i would like to aquire one of these ( as my arse is to soft and the data is getting lost on its way to the storage unit, my brain ( which is of a very limited size)

So I need assistance

What I would like is a Single channel with a 1/4 second sample rate that I can hook up a linear potentiometer.

Yup its for measuring suspension travel ( with the software I already have I should be able to make accurate chassis and shim stack changes )

Now the fly in the ointment,,,, Needs to be as cheap as possible.

I have seen kits available for 50 US dollars that hook though an serial port on your computer, the expensive bit is the Potentiometer ( 180 Euros )

At htis point I know, not a lot about these things ,,,So ANY input ( no pun intended ) is welcome

I would like to get one up and running by end of April

If there is a way of building one , that would be cool as I am sure there are others that could use one,

kind regards Stephen

[imdying]

Haven't ever used one, but would a 1/4 second sample rate be quick enough for suspension?

[Brian d marge]

Haven't ever used one, but would a 1/4 second sample rate be quick enough for suspension?


possibly a bit course, a faster sampling would be the way to go
Stephen

[RantyDave]

A hack-tastic response: Pull a non-optical mouse to bits and see how that works. It has a little wheel that passes through an optical sensor and measures movement to a great accuracy. Hook that up to the suspension ... magically write some software (snigger) ... and Robert's your father's brother.

Maybe you should investigate a less high-tech solution? Like, if you're just looking to measure overall travel would you not do better to attach something that makes a physical mark? A bit like the "high water" mark left by the movement of the seal on the damper - only deliberate...

Dave

[Brian d marge]

Have a zip tie on both suspension rods but that will only tell you the max travel ..Hadnt thought of the mouse , have a few lying around here ... maybe something could be rigged up

Stephen

[Monsterbishi]

And dependant on what languages you're good with, use a older non-usb palmpilot instead to acquiare the data, it's serial line voltage is 3.3v, works a treat.

[imdying]

A hack-tastic response: Pull a non-optical mouse to bits and see how that works. It has a little wheel that passes through an optical sensor and measures movement to a great accuracy. Hook that up to the suspension ... magically write some software (snigger)Yeah I could write that. Be a bit heavy carrying around a laptop though. I also code for Pocket PC (PDAs and the like), could possibly capture a serial data stream via one of those.... :)

[cowpoos]

you got those springs dude?

if you havn't hav u tryed running a shim or two less or maybe a combination of one less and few smaller diameter ones in the rebound stack and use more fork oil [ie: less air in the fork]...less air more air spring....sort of....you'll get what I mean...

[Brian d marge]

The springs will be here on sat ...( insert lazy basket I am ..in my defence I was sick !)

compression stack stays the same , up one onthe rebound face shim to comp for the stiffer spring ,,,,


PDA ,,like this idea ,,as I can buy then cheap as ,,I have a palm three somewhere around here doing nought ...

how does the signal input ,,,work???

Stephen

[Brian d marge]

So
a older wheel mouse , a pda ...( any fencing wire???)

Like it , real Mcgyver stuff this , might actuall work !!!!
:rofl:

Stephen

I will find al the bits when I get home and see what happens !

[geoffm]

Get a book: "Data power - racecar data aquisition" by Buddy Fey. Sorry, you can't have mine... but the library should be able to get it through interloan.
Most of the cheap data aq units require a connection to the computer during data collection. Where and how are you going to mount the computer?
IIRC Rule of thumb is a 10x faster sampling rate than the frequency of the data you want to collect.
Geoff

[Brian d marge]

Get a book: "Data power - racecar data aquisition" by Buddy Fey. Sorry, you can't have mine... but the library should be able to get it through interloan.
Most of the cheap data aq units require a connection to the computer during data collection. Where and how are you going to mount the computer?
IIRC Rule of thumb is a 10x faster sampling rate than the frequency of the data you want to collect.
Geoff

Off to Amazon now !!
10x the rate you want ,,,,thats interesting ...

As for mounting the computer ...on the passenger seat where it usually stays , when its playing the Mp3 collection ...:2thumbsup

No Actually , I will get as much info first and see what we end up with ..

The more discussion throws up gems such as you provided ..,,,Heath Robinsons going to be real proud of this little effort !!!:spudbn:
Stephen


Just came back from Amazon ...350 US for that book ...OUCH

[geoffm]

if you want books, look at www.abebooks.com and www.bookfinder.com - both second hand book search engines. Good way to get out of print books, or cheaper than new.
Geoff

[rogson]

Jaycar Electronics sell a 4 channel data logger for NZD170 (catalogue#QD5000) - link below. Sample rate up to 100/second.

Displacement transducers are available in various stroke lengths. I bought a 100mm one for about NZD200 a couple of years ago. From memory they were available up to 400mm. I can't recall where I bought it but I could probably dig-out the paperwoerk if you are interested.

[URL="http://jaycar.co.nz"[/URL]